Question

2. A TV set, a stove, a flat iron are connected in series to a 220 V line. The resistance of the TV set is 20 ohms, the stove is 50 ohms and the flat iron is 35 ohms. Find the following;

(a) total resistance

(b) the amount of current flowing in each device

(c) the voltage drop across each device

Answer 1

(a) total resistance

$$R=R_1+R_2+R_3\\ =20+50+35=105\:\Omega$$

(b) the amount of current flowing in each device

$$I_1=I_2=I_3=\frac{V}{R}\\ =220/105=2.1\:\rm A$$

(c) the voltage drop across each device

$$V_1=I_1R_1=2.1*20={42\:\rm V}\\ V_2=I_2R_2=2.1*50={105\:\rm V}\\ V_3=I_3R_3=2.1*35={73\:\rm V}$$